>>56243282These are my top ten sleepers over 500 hours, they've all seen a lot of use.
Not pictured is a level 44 Wigglytuff that sadly got obsoleted by a phenomenal shiny Igglybuff near Christmas.
Also have a level 17 Charmeleon with nearly 500 hours for some reason.
I'm currently sitting on 600 Jigglypuff candies and 1.2m dream shards.
The costs from 55 to 60 isn't currently known, however from 50 to 55 for most species is 353 candies and 121k shards.
I'm tempted to power level my Wiggly to 60 or as far as my candies will take her, because she unlocks 3x cacao at 60 which is great as an additional passive ingredient source atop 1x honey and 2x oil.